The invention concerns a device for injection of a two-phase mixture composed of fuel and carrier air into the intake pipes associated with the individual cylinders of a multi-cylinder mixture-compressing combustion engine. The device having carrier air apportioning means which apportion a carrier air current, branched off an intake manifold and conveyed by an air pump, to injection lines separately associated with the individual cylinders of the engine and opening into the intake pipes thereof. Further provided is a fuel injection valve which injects the fuel, by way of separate injection nozzles, into the individual injection lines. The carrier air apportioning means is provided with a carrier air collecting space formed in a housing containing the injection valve. The collecting space surrounds the injection valve in an annular manner and communicates with the air pump and the injection lines.
Such a fuel injection device has already been proposed by a previous European PCT application. Contrary to other previously known fuel injection devices in accordance with which a two-phase mixture consisting of fuel and carrier air is injected into the intake pipes of multi-cylinder mixture-compressing combustion engines, the metering and apportioning of the fuel as well as the apportioning of the carrier air is obtained according to said application separately to the individual cylinders of the combustion engine prior to the mixing of the fuel with the carrier air. Thus, the difficult distribution of the fuel-carrier air mixture which was necessary in case of the heretofore known fuel injection devices in which the fuel was injected centrally and for all cylinders together into the carrier air line can be dispensed with.
However, in the fuel injection device proposed by the previous PCT application, the arrangement of the injection lines, in particular in the region of the zones situated ahead of the fuel delivery points in the direction of the flow, is still unfavorable in that a sufficiently precise apportioning of the carrier air to the individual injection lines is not possible without difficulty and, moreover, there is a risk that the fuel which is delivered will flow back, in opposition to the direction of flow of the carrier air, into the carrier air collecting space and will collect there in low-lying points.